In recent years, accompanying the improvement in performance and reduction in size of an image pickup apparatus using a solid-state image sensor, such as a charge coupled device (CCD) type image sensor and a complementary metal oxide semiconductor (CMOS) type image sensor, mobile telephones and portable information terminals including such an image pickup apparatus are spreading. Further, an image pickup lens mounted in such an image pickup apparatus is demanded increasingly for further reduction in size and improvement in performance. As an image pickup lens intended for such a use, there has been proposed an image pickup lens having a configuration of five lenses because of the possibility of improvement in performance compared to a lens having a configuration of three or four lenses.
As an image pickup lens having a configuration of five lenses, an image pickup lens has been disclosed, which is configured by a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, a fourth lens having a negative refractive power, and a fifth lens having a negative refractive power in this order from an object side (for example, Patent Literature 1).
Further, an image pickup lens has been disclosed, which is configured by a first lens having a negative refractive power, a second lens having a positive refractive power, a third lens having a negative refractive power, a fourth lens having a positive refractive power, and a fifth lens having a negative refractive power in this order from the object side (for example, Patent Literature 2).
However, in the image pickup lens described in above Patent Literature 1, the first lens to the third lens contribute to most of the refractive power of the entire system and the fourth lens and the fifth lens have only the effect as an image plane correcting lens having a weak refractive power. Consequently, the image pickup lens of Patent Literature 1 has such a problem that aberration correction is insufficient and if the total length of the lens is reduced, it becomes difficult for the image pickup lens to cope with a larger number of pixels in the image sensor because of deterioration in performance.
Further, in the image pickup lens described in above Patent Literature 2, the former group configured by the first lens and the second lens includes a spherical surface system, and therefore, it is not possible to secure excellent performance because of insufficient correction of spherical aberration and comatic aberration. Furthermore, in the image pickup lens of Patent Literature 2, because not only the former group but also the latter group including the third lens and subsequent lenses has a configuration of the positive refractive power, the principal point position of the optical system is on the image side and the back focus (distance from the last lens surface to the image plane) is increased, and therefore, this is a type disadvantageous in downsizing.